When you substitute P and Q you should get wrong equation, then it will have no solution.
A) -68x-68=-68x+34
-68 = 34 False, no solutions
B)-68x+68=-68x+34
68=34 False, no solutions
C)-68x-34=-68x+34
-34=34 False, no solutions
D) -68x+34=-68x+34
34=34 True , so this equation will have infinite number of solution.
A,B,C have no solutions, D has infinite number of solutions.
